It's been my experience that there aren't that many "small jobs" for an auction, but there are tons of medium-big jobs, and a couple of very BIG, IMPORTANT jobs that shouldn't be divided.
Specifically, we've always had good luck with ONE Donation Inventory Manager. That is, one person whose house is used for storage of donated items and whose job it is to keep a running inventory of all donations actually procured. You could concievably have someone else in charge of getting the donations and following up on leads, but once the item actually comes in, it goes to the storage house and gets logged by the inventory manager.
We also have had great luck using MS Access (database) for creating our auction catalog. The database also allows us to create our bid sheets, item labels, thank you notes, donor lists, statistical reports, and more. But...it's a one person job since all the info resides on one computer and it's a bit complicated to use. The Inventory Manager turns over the information of what is an actual auction "lot" (because it may be made up of several donated items) to the Database Manager who then loads the info into Access. If your group isn't using a tool like Access, another set of jobs includes creating the bid sheets themselves, and the auction catalog-neither of which I would classify as small, unfortunately.
I'm not sure I saw "cashier" on your list of jobs. We've worked on refining our cashing out process because it can quickly become a bottleneck that could spoil an otherwise great evening. Depending on the size of your event, you might need 4-6 adults to be cashiers. Don't leave this as an afterthought - consider the traffic flow, supplies/equipment needed (ex: calculators, pencils, receipts, etc.), lighting, filing boxes, etc. I would definatley have one person in charge of the planning, setup and training, and several actual cashiers.
We used highschool honor society students for our runners the night of the auction. So, another job can be to recruit, train, and supervise the students at the auction.
Decorations? Is that on your list? Depending on your venue, your decorations team could go crazy or simply order a few flower arrangements.
How about Auctioneer schmoozer? If you have a "celebrity" auctioneer for your live auction, maybe assign one person to be his/her contact that night.
Ok, that's all for now, dinner's calling.